This invention relates to a diaphragm for use in acoustic instruments such as speakers and microphones. This invention also pertains to a method of manufacturing an acoustic diaphragm.
To improve the performance of acoustic diaphragms, attempts have been made to reduce the density and increase the Young's modulus for materials from which diaphragms are made. One example is a honeycomb structure having a honeycomb core sandwiched between skins. The advantages of the honeycomb structure are light weight and rigidity. In the prior art, aluminum or fibrous carbon in a resinous matrix is used for the skin and aluminum is often used for the honeycomb core. Since these structures have a relatively large mass, and particularly a low specific modulus of elasticity E/.rho. (E is Young's modulus and .rho. is density) in the case of resin-bonded carbon fiber, the acoustic characteristics of the resulting diaphragms are not satisfactory. Furthermore, it is actually very difficult to form a honeycomb core from aluminum without a special complicated technique. This increases the cost of aluminum honeycomb diaphragms.